在 readdir 中使用 readdir 后如何向客户端发送数据

Question

我需要读取一个名为 'curvas' 的文件夹。 'curvas' 中有很多文件夹，我正在使用 readdir 来获取它们。获取 'curvas' 内的文件夹后，我正在执行 foreach 并使用 readdir 列出文件（'curvas' 内的文件夹内的文件）。

问题是我只能访问内部 readdir 中的变量（我用 console.log 测试过）。

问：如何访问这个变量并用 res 响应客户端。？

这是我的进展：

exports.getInserted = async function (req, res) {

    var teste = await getFilesNames(); // HERE I NEED TO GET THIS FILES NAMES WITH FOLDERS
    console.log(teste); // AND THEM PASSING TO THE CLIENT WITH RES.SEND()

};

function getFilesNames() {
    return new Promise(function (resolve, reject) {

        const chartFolder = './curvas/';
        var fileNames = [];

        fs.readdir(chartFolder, (err, folders) => {

            if (err) {
                reject(new Error("Erro ao ler os arquivos."));
            }
            folders.forEach(folder => {
                fs.readdir(chartFolder + folder, (err, files) => {
                    fileNames = files;
                    console.log(files) // ----- HERE I CAN SEE ALL FILES AND LIST WITH THEIR FOLDERS.
                });
            });
            // I NEED USE resolve(fileNames) HERE, BUT IS EMPTY!!
        });
    });
};

谢谢！

[编辑]

解决方案： @omarwaleed 指导

    exports.getInserted = async function (req, res) {

    // Envia os arquivos das pastas de curvas para o cliente.
    var data = await getFilesNames();
    res.status(200).send(data);

};

function getFilesNames() {
    return new Promise(function (resolve, reject) {

        const chartFolder = './curvas/';

        // take care. I've turned it into an async function here
        fs.readdir(chartFolder, async (err, folders) => {

            if (err) {
                reject(new Error("Erro ao ler os arquivos."));
            }
            let promiseArray = [];
            folders.forEach(folder => {
                promiseArray.push(
                    new Promise((resolve, reject) => fs.readdir(chartFolder + folder, (err, files) => {
                        if (err) {
                            reject(err);
                        }
                        resolve({
                            folder: folder,
                            files: files
                        });
                    }))
                )
            });
            let results = await Promise.all(promiseArray);
            resolve(results)
        });
    });
};

Answer 1

使用 resolve 代替注释 // I NEED USE resolve(fileNames) HERE, BUT IS EMPTY!! 将导致未定义的 resolve 语句，因为第二个 fs.readdir 将运行异步，这意味着目录将在您的代码之后读取解决。为了解决这个问题，我建议你用 promise 包装 fs.readdir ，你可以等待所有文件的读取并解决响应
您的函数如下所示

function getFilesNames() {
    return new Promise(function (resolve, reject) {

        const chartFolder = './curvas/';
        var fileNames = [];

        // take care. I've turned it into an async function here
        fs.readdir(chartFolder, async (err, folders) => {

            if (err) {
                reject(new Error("Erro ao ler os arquivos."));
            }
            let promiseArray = [];
            folders.forEach( folder => {
            promiseArray.push(
              new Promise((resolve, reject)=>fs.readdir(chartFolder + folder, (err, files)=>{
                if(err){
                  reject(err)
                }
                resolve(files)
              }))
            )
        });
        let results = await Promise.all(promiseArray);
            resolve(results)
        });
    });
};

在 readdir 中使用 readdir 后如何向客户端发送数据

How can I send data to the client after use readdir inside a readdir

asynchronous

readdir

node.js

promise

express